Method for guaranteeing quality of service on the internet by routing data along nodes without error correction processing capability

ABSTRACT

This simple ready method routes all data (eg IP packets/ATM cell) between source and destination only along non-blocking links of router nodes on the Internet without data portion checksum processing at the nodes (eg using Real time Streaming Protocol IPv4 UDP packet type with checksum disabled; or as IPv6 specified hops UDP packets which has checksum included in the data portion but routed only along cut-through router/switches). The IP Packet here is sent without error correction checksum in the data portion, or the nodes along the route do not perform any error controls on the data portions of the IP Packets/ATM cells. Hence there will not be any IP Packets/ATM cells retransmissions occurrence along the route. IP Packets/ATM Cells with Header portion checksum errors detected could simply be discarded.

At present to facilitate multimedia/voice/fax/realtime applications onthe Internet requires the IP packets to be given priority over otherpackets by methods such as RSVP/Tag Switching/guaranteed QoS ATM flowetc to ensure Quality of Service. However, the lack of interoperablestandards means that the promised ability of some IP technologies tosupport these value-added services is not yet fully realised. Only avery small percentage of the routers/switches on the Internet at presentare ATM router/switches.

Here is described a simple ready method enablingmultimedia/voice/fax/realtime applications with similar end to endreception qualities on the present existing Internet InfrastructureTechnology, and present existing protocols, without requiring RSVP/TagSwitching/guaranteed QoS ATM flow etc to ensure Quality of Service. RealTime Data may be transmitted over present existing Internetinfrastructure, using present existing protocols, over the Internet to awider number of Internet users.

This simple ready method routes all data (eg IP packets/ATM cell)between source and destination only along non-blocking links of routernodes on the Internet without data portion checksum processing at thenodes (eg using Real time Streaming Protocol IPv4 UDP packet type withchecksum disabled, or as IPv6 specified hops UDP packets which haschecksum included in the data portion but routed only along cut-throughrouter/switches). The IP Packet here is sent without error correctionchecksum in the data portion, or the nodes along the route do notperform any error controls on the Data portions of the IP Packets/ATMcells. Hence there will not be any IP Packets/ATM cells retransmissionsoccurrence along the route. IP Packets/ATM Cells with Header portionchecksum errors detected could simply be discarded.

Not all incoming links of the nodes routed through need be non-blocking,as long as the links routed through between source and destination arenon-blocking.

An Internet connectivity map/database can be set up allowing Internetusers to access, query and obtain the routes satisfying above examplecriteria.

Each such non-blocking nodes along the route introduces a small fixedhardware port to port latency, say around 8-30 microseconds each; with a20 hops route the total port to port latency will introduce around160-600 microseconds minimum delay to the supposed wire-speed source todestination data transmissions which we want to achieve.

For movies and telephony applications, delay of less than 0.02 seconddoes not cause noticable impairment to the perception qualities. VoicePCM data may thus be conveniently transmitted as IP packet as in presentexisting practise, but routed as above only along non-blocking links ofrouter/switches nodes on the Internet.

Here very close approximation to wire-speed transmissions is achieved.The example extra 160-600 microseconds delay in end to end transmissionswill not be cause noticable perception impairment to end users.

As an example, to ensure the IP packets/ATM cells etc are routed as inabove examples, the periodically sampled data may be transmitted fromthe source as deterministic (ie always follow the same fixed path)unicast IP packets/ATM cells, eg using Real Time Streaming Protocol IPv4UDP packet type with checksum disabled or as IPv6 specified hops UDPpackets which has checksum included in the data portion but routed onlyalong cut-through router/switches.

The Movies interframes/voice PCM inter-samples received at destinationPC, transmitted using this simple method, would exhibit very minimalinter-packet arrivals jitters, enabling Cinema quality viewing of realtime Internet streaming and very similar to PSTN quality Internettelephony.

Its noted here that the Last Mile could be DSL; or special non-blockingdial-up link port implemented, eg by end user's ISP provisioningsufficient switching processing capacity.

Limited blocking links may also be selected between the source anddestination, eg Head of Line blocking could be tolerated where any delayencountered would only be for the very finite duration for therouter/switch to complete its pre-existing forwarding operation on asingle IP Packet/ATM Cell, from each of the node's incoming links, ifany, onwards along the same outgoing link. Or eg where the individualnodes traversed is a Store & Forward router/switches or Cut-Throughrouter/switches but where the data here is sent as Priority IPPacket/Priority ATM cell with priority in processing over any othernon-priority IP Packets/ATM cells already in the queue buffer, each ofthe nodes imposes traffic management with neighbours ensuring that thesum of priority traffic from various preceding incoming links at anytime does not exceed the available outgoing link bandwidths/switchprocessing, capacity. [An example of priority IP Packet: the Type ofService (TOS) fields in IP Header allows an originating host to requestdifferent classes of service for packets it transmits.]

The above-described embodiments merely illustrate the principles of theinvention. Those skilled in the art may make various modifications andchanges that will embody the principles of the invention and fall withinthe spirit and scope thereof

1. A method for routing data (eg IP Packets/ATM cells) between anysource and destination on the Internet/WAN/Intranet, said method routedata (eg IP Packets/ATM cells) by selecting only non-blocking links ofrouter/switches nodes for forwarding of the data between source anddestination on the Internet/WAN/Intranet.
 2. A method for routing data(eg IP Packets/ATM cells) between source and destination on theInternet/WAN/Intranet, said method route data (eg IP Packets/ATM cells)by selecting only non-blocking, and/or limited blocking links, ofrouter/switches nodes for forwarding of the data between source anddestination on the Internet/WAN/Intranet.
 3. A Method as in Method 2above, where the only limited blocking of the link can arise only fromHead-of-Line blocking, the delay encountered hence is only for the veryfinite limited duration for the router/switches to complete pre-existingforwarding operation on the single IP Packet/ATM Cell, from each of thenode's preceding incoming links, if any, onwards along the same outgoinglink.
 4. A Method as in Methods 1 or 2 or 3 above, where the individualrouter/switches nodes traversed may be a Store & Forward router/switchesor Cut Through router/switches, here the data (eg IP Packets/ATM cells)is sent as Priority IP Packets/ATM cells with immediate priority inprocessing over any other non-priority IP Packets/ATM cells already inthe queue buffer; each of the nodes imposes traffic management withneighbours ensuring that the sum of such priority traffic from variouspreceding incoming links at any time does not exceed the availableoutgoing link bandwidths/switch processing capacity.
 5. A Method as inMethods 1 or 2 or 3 or 4 above, said Method route the data (eg IPPackets/ATM cells) along nodes without data portion checksum processingat the nodes hence there will not be any IP Packets/ATM Cellsretransmissions occurrence on IP Packets/ATM Cells data portion checksumerrors between any of the neighbouring router/switches nodes along theroute.
 6. A Method as in Method 5 above, said Method route the data (egIP Packets/ATM cells) along nodes using, eg Real Time StreamingProtocol, IPv4 UDP packet type with checksum disabled; or eg IPv6specified hops IP/UDP Packets which has checksum included in the dataportion but routed only along cut-through router/switches: where theIP/UDP Packets/ATM Cells here are sent without error correction checksumin the data portion, or the nodes along the route do not perform anyerror controls on the data portions of the IP/UDP Packets/ATM cells. 7.A Method as in any of the preceding Methods above, said Method has anInternet connectivity map/database set up allowing Internet users toaccess, query and obtain the source to destination routes meeting therequirements of any of the preceding Methods.
 8. A Method as in any ofthe preceding Methods above, said Method has a special non-blockingdial-up link port implemented in the end users last-mile access, eg byend user's ISP provisioning of sufficient switching processing capacity.